This invention relates generally to an improved electric drive, and more particularly to a unique method and apparatus for providing magnetic drive detents in electric motors.
Motors incorporating the present invention have low mass, low inertia, low inductance or non inductive armature (non-ferrous air coil) which thereby permits high switching speeds.
The basic configuration for an electric drive according to the present invention is at least a pair of serpentine conductor members, constituted by windings or conductor elements having at least active portions, transverse to the direction of movement, sandwiched between an incremental alternately polarized or castellated permanent magnetic structure. Each of the phases of the windings is energized by phase displaced currents to establish magnetic driving detents between respective active portion traversals of the conductors with respect to the selected axis and the magnetic field-forming magnet structure. In a preferred embodiment, the serpentine conductor elements are printed on a non-conductive substrate and the stator magnetic fields are formed of high strength permanent magnets.
As used herein, the term "magnetic detent" means the combination of a pair of polarized magnetic fields, one of which is produced by permanent magnets and the other which is produced by one run or one active portion of a run of an armature winding or the combined activations of two or more windings. The term "attractive magnetic detent" means the combination of one magnetic field with a second magnetic field such that the two fields draw towards or are attracted to one another. The term "repulsive magnetic detent" means the combination of one magnetic field with a second magnetic field such that the sources of two fields repel or are repulsed relative to each other. As used herein the term "printed circuit" includes all conductor elements formed by techniques for forming conductive metal conductors on a substrate.
The above and other objects, advantages and features of the invention will become more apparent when considered with the following specification taken in conjunction with the accompanying drawings wherein: